Each category: Run (purple race bib), Jog (blue race bib), Walk (pink race bib) is allocated an arrival window instead of a set start time. You can arrive at any time during your arrival window to join the start line.
There will be a rolling start through the morning with each category flowing through the start line during the arrival window timeframes.
For more information relating to your arrival window please see the following link that outlines each of the categories.